Revs dropped, engine cut out

P

PawnSacrifice

Veteran
 South Oxfordshire
Had a bit of a worry on my recent trip across Europe - the engine cut out... half way up the Stalvio Pass :o

Scenario:
Tuesday last week I drove from France to Switzerland. Wednesday I drove the Kleusen, Fluela, and Stelvio passes. Due to the brakes playing up after the decent from the Kleusen I used the engine to help with the braking on the Fluela. I stopped for about half an hour for lunch and then pressed on to the Stelvio. On the Stalvio, once traffic got out of the way I started to press on:
Hairpin, 1st gear, full throttle, 2nd gear, full throttle. Brake, hairpin. Repeat.
10-15 minutes of the above, after a change to 2nd, the engine dropped to about 3,000rpm, the throttle full open, the revs just dropped away. I put the clutch in and the engine stalled.
There were no warning lights, no fluid leaks, the temperature gauge was dead centre and engine (when started) didn't make any odd noises. I pulled away gently, but after the hairpin, on the change to 2nd, the engine stalled again. I did this once more before pulling to the side of a long (for the Stalvio) straight. After 5 - 10 minutes I set off slowly and made it to a car park, opened the bonnet and took some pictures (will post soon). I waited at least 20 minutes before setting off and the car was fine (apart from the damn Greenstuffs - but that's for another thread :x )
IIRC it was 28c to 34c on the Stalvio, although cooler than previous two passes.

I progressed slowly to the bottom of the pass and then proceeded normally on the normal roads. Once I'd made it to Milan it was 90mph - 100mph for the next couple of hours, engine ran perfectly. I've done probably another 1,000 miles since then, including more passes :) and the engine has been perfect. Most odd.

Anyone have this? Any ideas what may have caused it?

I will be getting the car into my indi so they can check the codes I can't see.
 
Always difficult when there are no other indications or visible signs of the fault. Agree in the first instance with Gannet and obviously without any further diagnosis that the switch back ride on the pass may have just dislodged some debris in the fuel tank causing a temporary blockage. Whilst there will be a thinning of the air at 9,000 feet I wouldn't have thought this would have been sufficient to cause any difficulties in the engine however combined with high reasonably high temps this may have had some effect on throttle response. More likely to be a fuel filter issue where a blocked or dirty filter will usually pass enough fuel to keep the engine running at idle or low speed, but may starve the engine for fuel at higher speeds or loads. So the engine may respond at low revs and low fuel demand, but sputter and lack power when you try to drive at higher speeds. Keep us updated!
 
Thanks guys - reassuring that none of you were horrified that I kept going. Fuel was my first thought... actually, oh crap I'm buggered was my first thought! Then fuel.

I am pretty sure that up to that point I'd been using Shell V-Power - despite the fact that I couldn't use my loyalty points card :( Otherwise it was always the high octane choice from a brand I recognised. Fuel definitely wasn't low - I always made sure the OBC miles of fuel remaining figure was at least 75 more than the distance to my destination.

About 1,000 miles before this happened the car had it's Inspection II.
 
Id very much doubt it was fuel to just kill the engine like that, you'd usually get a stuttering warning beforehand as a minimum. The pipe/filter shouldn't just block spontaneously, you loose a few injector cycles to start off with.

Did you not get an EML? It may be worth getting a scanner on there regardless if there are any...

If my flying knowledge serves me correctly, you loose around 3% of air pressure per 1000'. Near the summit of Stelvio, you loose 9000' worth, which is ~27.5%, quite a lot!! This is a direct correlation to power in an NA car (you loose less in a Turbo as the Boost is constant and not dependant on ambient pressure)

I know the M54 has a MAF&MAP combination which should avoid this but... When an engine is flat throttle, it is running in open loop. This doesn't use the lambdas to correct mixture. Maybe, as you were either flat out or coasting, the ECU didnt lean off the mixture enough and the engine just flooded, or just got totally confused? I don't suppose you noticed any black smoke did you?

You often see many new cars on these roads being test driven as it totally maxes out the Engine, ECU, sensors etc, as well as the chassis and brakes in the corners... Hope you enjoyed it! :D :driving:
 
EdButler said:
I know the M54 has a MAF&MAP combination which should avoid this but... When an engine is flat throttle, it is running in open loop. This doesn't use the lambdas to correct mixture. Maybe, as you were either flat out or coasting, the ECU didnt lean off the mixture enough and the engine just flooded, or just got totally confused? I don't suppose you noticed any black smoke did you?

You often see many new cars on these roads being test driven as it totally maxes out the Engine, ECU, sensors etc, as well as the chassis and brakes in the corners... Hope you enjoyed it! :D :driving:
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Thanks Ed, always enjoy seeing some facts! Only reason I'm not sure about the air pressure is that this happened a little way from the top, maybe 1000 - 1500 ft down. On Sunday I was pretty much driving through cloud on another pass at similar altitude with no issues at all. Although that was a lot colder - around 7c. Very odd behaviour, especially as the car had just been serviced and dynoed and all indicated it was tip top :?

Am desperate to get to the indi, but that might not be until next week. May have a look through the TIS this weekend, though not expecting to find anything.

And yes, trip was fantastic! Well it would be, Road Trip kindly sorted a route for me :driving:
 
PawnSacrifice said:
Very odd behaviour, especially as the car had just been serviced and dynoed and all indicated it was tip top :?
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Like UK MOTs servicing is only a check on functionality at the time of the service and not a predictor of future failure. Hope its gets sorted and you have no more issues. :thumbsup:
 
Or even stronger - whenever I have had problems with any car, it has always been AFTER a service and not before.
 
AlanJ said:
Like UK MOTs servicing is only a check on functionality at the time of the service and not a predictor of future failure. Hope its gets sorted and you have no more issues. :thumbsup:
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Not very well explained on my part, I was thinking more that it ruled out dirty oil, filters, plugs etc Also the car was recently Dynoed and the results were very good, for the age of car - and the runs were very consistent :)

pvr said:
Or even stronger - whenever I have had problems with any car, it has always been AFTER a service and not before.
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Well, that blows my theory above, that the service made things better :?

The car feels great again now, probably just one of those odd things, I'm now curious more than anything else.
 
pvr said:
Or even stronger - whenever I have had problems with any car, it has always been AFTER a service and not before.
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Sometimes BUT not always servicing a car brings back some items to optimum efficiency which then highlights other issues which may have degraded over time. New plugs may exacerbate an issue with a coil pack. Just a thought.
 
PawnSacrifice said:
Am desperate to get to the indi, but that might not be until next week. May have a look through the TIS this weekend, though not expecting to find anything.

And yes, trip was fantastic! Well it would be, Road Trip kindly sorted a route for me :driving:
Click to expand...

I'm a bit late to this thread! Drop me a copy of that route if you can, it's pretty much where I'm intending on heading in a couple of weeks time :)

If you've not managed to get to a dealer before Scotland then I'll have my OBD2 reader with me so we can have a look then :)
 
Taz x said:
OBD2 reader?
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Plugs into the little plug on the right hand side, below the steering wheel and above the boot/bonnet release catches.

Lets you read off the error codes from the engine - fitted to all cars after about 1991 or so. Basically what the garages use to work out what's up with cars nowadays.

Better description from someone who knows what they're talking about here: http://en.wikipedia.org/wiki/OBD2#OBD-II
 
Siftah said:
I'm a bit late to this thread! Drop me a copy of that route if you can, it's pretty much where I'm intending on heading in a couple of weeks time :)

If you've not managed to get to a dealer before Scotland then I'll have my OBD2 reader with me so we can have a look then :)
Click to expand...

Thanks mate, have the car booked into the indi at 8:00am on Friday, they're going to check the GreenStuffs too.

Reference the route, have a look at this thread: Trip to Tuscany - Switzerland / Italy | Now Added Video
:D
 
Took the car into the indi this morning, wasn't showing any errors. Oh well, put it down to one of those things, car is running fine and the mechanic said there was little value in them manually chasing down a fault that may not even be there.

Ho-hum... off to the Skye meet in a couple of hours :D
 
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